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SW2 flows were sporadic. In recent years flows at SW -I have been minor, and in the case of SW -2, non- <br />existent. Flow was observed in SW -1 in April, but it was dry in September of 2015. See tables 51 and 52. <br />In April 2015, a spring and seep survey was also conducted in the northern mining district to identify potential <br />discharges to Fish Creek. No new or significant springs were identified in 2015. The northern mining district is <br />located within the Twentymile Park Syncline. The predominant lithologic unit nearest the surface and occupying <br />most of the basin is the Lewis Shale, which can be upwards of 700 feet thick. The lack of significant bedding <br />planes, faulting, or fracture zones in this area may account for the lack of springs in the central portion of this <br />basin. The few seeps observed in the basin may be the result from surface weathering of the Lewis Shale, which <br />may allow some accumulation of water beneath overburden. This may result in a short period of seepage <br />immediately following spring runoff. <br />3.6 CDPS Discharge Sites <br />Under State of Colorado Department of Public Health and Environment (CDPHE), Colorado Discharge Permit <br />System (CDPS) permit No.'s CO -0027154, CO -0036684, and CO -0042161, eleven discharge points are <br />monitored throughout the year. Note that CDPS has also been referred to as the National Pollutant Discharge <br />Elimination System (NPDES) in previous AHRs. Monitoring results (CDPHE Colorado Discharge Monitoring <br />Reports, or DMRs) are copied to DRMS in accordance with CDPS requirements. Tables 54 through 60 provide <br />2015 and historical data summaries for those CDPS outfall points. Figures 110 through 116 provide graphical <br />representations of the 2015 flow rate and field conductivity data for the discharge ponds. <br />Note that ponds A (former Outfall 001A), and H (former Outfall 009A) were deactivated following Phase III <br />Bond release of the Eckman Park area, and were subsequently removed from the newly amended CDPS permit <br />on January 1, 2002. In late 2011 and early 2015, the Fish Creek Tipple area was reclaimed. This along with the <br />2015 drought appears to have resulted in decreased discharge at the site. <br />Construction Dewatering Permit COG -850051 <br />In July 2006, Twentymile Coal contacted CDPHE regarding the addition of this site (drainage for 6MN Pad area <br />and construction dewatering pond) and later submitted a Temporary Construction Dewatering — Wastewater <br />Discharge Application, which was subsequently approved (Outfall 001A under CO -G072272). CDPHE requested <br />preliminary analyses of this water for alkalinity, COD, pH and TDS. A sample was collected and analyzed for <br />these parameters. A discharge channel was constructed in late July 2006, and weekly monitoring of discharge <br />from outfall 001A began in August 2006. Note that water was pumped from the sedimentation pond through <br />001 A on an as needed/ sporadic basis. Pump flows were estimated. CDPHE Discharge Monitoring Reports are <br />copied to DRMS. TC subsequently applied for a CDPS permit to make 6MN a permanent Outfall. A permit <br />(COG -850051) was subsequently approved in January 2010 by CDPHE, effective February 1, 2010, expiring <br />June 30, 2015. The permit is currently under Administrative Extension with CDPHE. <br />Outfall 001A did not discharge in 2015. <br />14 <br />